Although not exclusively, the present invention applies more particularly to a head-down-type display system which can display navigation information, such as an electronic screen of the EIS (Electronic Instrument System) type or a control and display system (CDS). Such a control and display system is notably described in French patent application n° 01 02566 and in French patent application n° 01 02567.
Said display system is of the type comprising:    a plurality of display devices, each of which comprises at least one associated viewing screen; and    at least one cursor management means enabling a pilot of the aircraft to move at least one cursor which can be moved over said viewing screens, and enable a sensitive (interactive) object that is designated by this cursor, in order to have a particular function associated with this sensitive object executed.
In the display system disclosed by the abovementioned patent application n° 01 02566, some of the viewing screens are intended for a first pilot, particularly the navigating pilot, others are intended for a second pilot, particularly the copilot, and yet others are common to said first and second pilots.
To ensure great effectiveness, each pilot is normally free to display the formats that he wants on the various screens that are allocated to him, and at any time. For this, each display device comprises an electronic control panel enabling the pilot to configure the display produced on the corresponding viewing screen. Also, regarding the display relating to navigation, different display formats (hereinafter called “navigation formats”) are normally available.
Also, because of the many possible display configurations, the displays implemented on the various display devices, even those that are intended for one and the same pilot, can vary widely. In particular:    certain modes can be oriented towards the north, others can be oriented in the heading of the aircraft, and yet others can be fixed according to a stored heading;    the display radii can be very different; and    the display contents can also be different, some displays possibly being intended for navigation and others reserved for a tactical symbol system, for example.
Such a usual display system presents a few drawbacks, and in particular:    the viewing screens intended for one and the same pilot can be geographically decorrelated even when they display a navigation format, and it can be very difficult for the pilot to geographically correlate two navigation formats before performing an interactive action (replanning the flight plan, analyzing the terrains around a drop zone, etc.); and    a lack of communication between two viewing screens that are intended, one for a first pilot and the other for the second pilot.